FIRST STOP: Soviet Union's Salyut Stations
Tragedy struck the station's mission when the second crew to visit, aboard Soyuz 11, experienced depressurization during their return to Earth, killing all three cosmonauts. The station did not host any further visitors. The Soviet Union then attempted to orbit stations DOS-2, Salyut 2 and Cosmos 557, but failed. Salyut 3 experienced some flaws, while Salyut 4 and Salyut 5 completed their missions successfully.
NEXT: Salyut 6 and 7
Durations of stays increased, and crews could receive visitors. A Salyut 6 crew stayed for 185 days, the longest duration at that time, beating the 84-day record of the last Skylab crew. Salyut 6 launched in 1977 and deorbited in 1982. Salyut 7 launched in 1982 and deorbited in 1991. [Top 10 Russian and Soviet Space Missions]
NEXT: Skylab, NASA's 1st Space Station
The first crew that arrived 11 days later had to confront many frustrating challenges. Having overcome the initial difficulties, three three-person crews visited the station.[Photos: Skylab, the 1st U.S. Space Station]
The third crew set a record of 84 days in space, but not without complaint about overwork, which led to tensions and finally compromise with ground controllers. Skylab deorbited on July 11, 1979, well ahead of schedule because of high solar activity, with some spacecraft parts accidentally impacting Western Australia. Notably, the impending re-entry of Skylab produced a huge media reaction, and inspired a hilarious rant by John Belushi on the Saturday Night Live television show. [See photos of Skylab debris in Australia]
NEXT: Mir, Russia's Long-Lived Outpost
During that time the Soviet Union dissolved. (The cosmonaut aboard Mir at the time, Sergei Krikalev, is sometimes known as "the last Soviet citizen" as a result.) The long-lived Mir hosted every record-setting visitor in long-duration spaceflight. Physician Valeri Polyakov lived aboard Mir for a bit over 437 days, still the record. [Most Extreme Human Spaceflight Records]
During the Shuttle-Mir Program (1994-1998), even American astronauts visited the station. As the station aged, it developed numerous problems including an infamous onboard fire. Planning for the International Space Station eventually overtook Mir's resources, and it deorbited in 2001. Concerns about space debris again alarmed many, but the pieces of Mir fell harmlessly into the southern Pacific Ocean.
NEXT: Tiangong 1, China's 1st Space Lab
As Tiangong 1 is largely considered a prototype for a larger station, it is expected to be deorbited in 2013 after two years of operation.
NEXT: International Space Station
Built in sections, the station began in 1998 with the launch of Russia's Zarya's module. Today it spans the area of an American football field, possessing numerous pressurized and unpressurized modules. [Rare Photos: Space Shuttle at Space Station]
Humans have continuously occupied the International Space Station since Nov. 2, 2000. In that time, 204 individuals have visited it. As of July 2012, 125 vehicles have launched to the space station since the launch of the first module: 81 Russian vehicles, 37 space shuttle missions, the U.S. SpaceX Dragon commercial vehicle (several missions), three European and three Japanese vehicles. The first crews consisted of three-person teams, dropping to two after the Columbia shuttle disaster, but as of 2009, six people can stay aboard the station at one time. Two Russian Soyuz modules remain docked to the station for crew departures.
The ISS receives commands from mission control centers in Houston or Moscow. The station has funding to operate through 2020, though it may remain capable of usefulness through 2028. [Video Show: See Inside the International Space Station]